GPR and ERT Application for the Detection and Characterization of NYF-type Pegmatite Deposits in Tysfjord, Norway

GREENPEG (2020–2024) is a Horizon2020 project funded by the EU and aims at the development of multi-method exploration toolsets for the discovery of pegmatites mineralized in lithium and high purity quartz. The project intends to provide a sustainable and economical exploration toolset for small volume (<5 million m3), high quality ores, with the goal to lower EU’s dependence on imports of critical and strategic raw materials. Three demonstration sites were selected across Europe, one of which is Tysfjord in northern Norway where high purity quartz is produced from NYF-type pegmatites. The Geological Survey of Norway (NGU), one of thirteen partners of the GREENPEG project, was tasked with testing the efficiency of ground geophysics at the Jennyhaugen open pit. The methods that produced the most promising results were Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT). The results verify that ground geophysics and in particular the combination of GPR and ERT can operate as an effective and sustainable tool for delineating and characterizing buried pegmatites at prospect scale (<25 km2). Detection on the other hand, utilizing generic dielectric and geoelectric properties such as lack of reflectivity and extremely high resistivity blobs, renders pegmatite mapping challenging.